Process for the scientific curing of woods.



erase arnur rue.

FRANK A. PALEN, or NEW YORK, N. Y.

ncome.

N0 Drawing.

To all u /2.0m if may concern Be it known that I, FRANK A. Panes, a

citizen of the United States, residing at New York, in the county of NewYork and State of New York, have invented certain new and usefulimprovements in Processes for the Scientific, Curing of iVoeds, of whichthe following a specification.

An object of my invention is to provide an improved process whereby anetlicient preservation can be obtained uniformly throughout the entirethickness of the wood, without injuriou. checking or disruption of thewood fibers.

A .t'urthcr object of my invention is to provide an improved process, bywhich the thoroughly d ricd-and hardened wood fibers will be protectedthrou glmut the mass by a coating or varnish of tlie undecomposed woodresins.

in previous processes'ilor treating woods, the unheated wood has beeninitially sub jected to a vacuum to remove all water and readilyvolatile aqueous matters, preliminary to treating the wood with heat inthe presence of a vacuum. It has been found that such initial vacuumtreatment causes localized drying in the outer layers of the wood,whereby said dried outer layers are injuriously checked and disrupted bythe heat employed in the succeeding step, and

act to retard pent-:tration of the heat to the interior wood layers andto entrap and retain the moisture in said inner layers.

in the preferred operation of my invention, the undried wood is placedin a suitable receptacle or retort and subjected to a progressivelyincreasing temperature in the presence of a vacuum of ap roximately 520to '28; the temperature being gradually raised to a maximum preferablybelow 300 F. and above the. point of sterilization. In this step, thegradually increasing temperature causes a progressive penetration of theheat through the entire thickness of the wood, whereby the escape ofaqueous vapor from the interior prevents initial drying of the outerwood layers, and enables a thorough" drying to be obtained uniformlythroughout the wood without injurious checking; thereby placing the woodin condition for insuring hardening of the wood fibers withoutdisruption of the latterand uniform coating of said fibers by the un-'decolnposed wood resins, in the succeeding steps of my process. Thevacuum is then Specification of Letters Patent.

Application fi-lcd November 20, 1911. Serial No. 661,394.

Patented July 8, 1913.

broken and the wood subjected to either dry or moist heat at atemperature below that which would cause decomposition of the woodresins and above the point of sterilization for a sutiicient time toproduce a substantially uniform temperature throughout the mass of thewood, thereby avoiding injurious fiber strains and warping of the woodand thoroughly hardening the wood fibers. Where moist heat is employedin this step, it can be conveniently provided by admitting steam,preferably superheated, to the retort. or by cuttin r oil the vacuum ofthe preceding step before complete remoral. of the aqueous matters hasbeen produced thereby. The wood is then subjected to the combined actionof a vacuum of approximately 20 to 29" and dry heat, preferably below380 ll, to cause vaporization oi the lighter oils and resins andliquefaction or'partial liquefaction of the heavier oils and resins inan undecomposed form and a uniform distribution of said undecompesedresins as an impervious coating or varnish on the sterilized wood fibersthroughout the mass.

By my above descrlbed improved process any possible locahzation byexcessive heating or drying; in the outer wood layers,

is avo ded, thereby insuring the necessary uniform drying: and heatingthroiu hout the mass of the wood to enable a uniform distribution of theundecomposcd resins as a protective coatiup on the wood fibers; there yeliminating the defects of previous )recesses, in which unil'orindistrilnition oi' the resins does not always take place and leavesportions of the wood fibers in condition for deterioratirm under thiaction of moisture and fungi growths. My invention provides a sterilizedhomogeneous product, free from weak portions and which cllicicntlywithstands warpinp; and checking under severe climatic conditions.

in the foregoing discussion of the operation of my improved process, Ihave employed the term resins or wood resins in its broadest, sense. itis, of course, obvious that some woods posdess practically no resins,but that they have s their equivulent heavy oils of a complex :hemicalcharacter, and gums of various kinds which act, when liquefied anddistributed, as a proteco tive coating for the wood fibers.

I claim:

-1; The herein described process of curing woochwhich consists in firstsubjecting the undried wood to combined action of a vacuum and aprogressively increasing tem perature, then breaking the vacuumandsubjectin-g the wood to heat alone to produce a substantially uniformtemperature throughout the entire mass without decomposition of the woodresins, and then subjecting the wood to the combined action of a vacuumand heat for causing distribution of the woodresins in an undecomposedform.

2. The herein described process of curing wood, which consists in firstsubjecting the undried wood to the combined action of a vacuum and aprogressively increasing temperature raised to a maximum below 300 R,then breaking the vacuum and subjecting the wood to heat alon for asufficient time j to produce throughout the. mass of the wood asubstantially uniform temperature below the temperature of'decompositionof the -'wood resins, and then subjecting the wood to thecombined action of a vacuum and heat for causing distribution of thewood resins in an undecomposed form.

3. The herein described process of curing ii 10nd, which consists infirst's'ubjecting the undried wood to the combined action of a vacuumand a progressively increasing temperature then wreaking the vacuum andsubjecting the wood to heat alone for a sufficient time to producethroughout the mass of the wood a substantially uniform temperaturebelow the temperature of decomposition of the wood resins, and then subjectmg the wood to the comblned action of a I vacuum and heat below'atemperature of 380 F.

4. The herein described process of curing wood, which consists in firstsubjecting the undried wood to a progressively increasing temperature inthe presence of avacuum, then breaking the vacuum and subjecting thewood to moist heat alone for a sufficient time to produce asubstantially uniform temperature throughout the entire mass withoutdecomposition of the wood resins, and then subjecting the wood to thecombined action of a vacuum andheat for causing vaporization of thelighter resins and uniform distribution; of the heavier wood resins inan undecomposed form.

5'. The herein described process of curing wood, which consists in firstsubjecting the undried wood to the combined action of a vacuum .andheatraised progressively to a maximum below 300 F., then breaking the vacuumand subjecting the wood to heat alone for a sufficient time to producethroughout the mass of the wood a uniform temperature below thetemperature of decomposition of the wood resins, and then subjecting thewood to the combined action of a vacuum andheat below a temperature of380 F.

In testimony whereof I aflix my signature in presence of two witnesses.

FRANK A. PALEN.

wane; B. Morrow, A. B. OHINNI.

